add experimental rules to build web site

We add to the top level Makefile, some initial rules that
will facilitate the building of HTML content.

The `bin/md2html.sh` tool as been updated to output HTML comments
about the output during HTML phases 20, 21 and 22.

All entry `index.html` files were updated with some additional HTML
comments as a result of the above.  The top level `location.html`,
`years.html` and `authors.html` have had HTML comments added also
a result.

Sorry (tm Canada 🇨🇦) for the mass update of entry `index.html` files.
Hopefully the times when all of them (often) need to be updated
will soon draw to a close.

1987/README.md

@@ -1,4 +1,4 @@
-# 1987 marked the "The Fourth International Obfuscated C Code Contest"
+# Fourth International Obfuscated C Code Contest
 
 Look at the README.md file for the given winning entry for information on how to
 compile it and how to run the winning program.  Look at the winning source and